1. Field of the Invention
The invention relates to techniques for above-ground cultivation (i.e., soil-less cultivation). More precisely, the invention relates to techniques in which cultivation employs several successive growth stages of the plants, each stage leading to the utilization of a substrate which offer a greater volume than that of the preceding one, to allow satisfactory development of the root system of the plant.
2. Discussion of the Background
In intensive modes of above-ground cultivation, good management of the materials and of the available space results in a succession of stages corresponding to the use of specific substrates.
The most common method currently in use in above-ground cultivation in greenhouses thus has at least two successive stages. The first stage corresponds to the initial growth of the plants. Since this does not require much volume and demonstrates limited development of the root system, professionals prefer to use a substrate with limited volume for this stage. This makes it possible to multiply the number of plants cultivated on a limited space. This also makes it possible to minimize the volume of nutrient solution necessary to keep this substrate in a condition that is adequate for the development of the plants. In a second stage, the plant which have grown on these substrates with limited volume are arranged, together with the first substrate, on a second substrate which offers a greater volume, and are ordinarily spaced apart from one another.